基于混沌加密和小波包分解的数字水印算法

提出了一种基于混沌加密和小波包分解的自适应数字水印嵌入算法.该算法首先利用混沌序列对水印图像进行预处理加密,使水印嵌入方案具有一定的安全性.然后根据信息熵选取最优小波包基,对宿主图像进行小波包分解变换.利用不同频域可以承受的信噪比不同的原理,在低频区域引入人类视觉系统,高频区域采用适当的阈值,分别计算出各频域的水印嵌入强度系数,自适应地嵌入水印信息.实验表明此算法使水印的嵌入达到了很好的抗攻击鲁棒性和视觉效果.

Digital watermarking algorithm based on chaotic encryption and wavelet packets

This paper presents an algorithm of self-adaptive digital watermarking based on chaotic encryption and wavelet packet decomposition.First,the image watermarking signal was designed and encrypted by a chaotic sequence cipher,made it have the certain security.Then by selecting the best bases of wavelet packet based on the information entropy,the host image is decomposed by wavelet set transform.Making use of the theory that different frequency region withstands different PSNR,the algorithm,introducing the human vision system(HVS)in the low frequency region and using the suitable threshold value in the high frequency region,calculates the embed strength coefficients of each frequency region and embeds the watermarking adaptive ness.Experimental results show that with this algorithm,we can embed the marks into the digital image with better anti-offensive robustness property and visual sense effect.